public interface Executor {
    ResultHandler NO_RESULT_HANDLER = null;

    int update(MappedStatement var1, Object var2) throws SQLException;

    <E> List<E> query(MappedStatement var1, Object var2, RowBounds var3, ResultHandler var4, CacheKey var5, BoundSql var6) throws SQLException;

    <E> List<E> query(MappedStatement var1, Object var2, RowBounds var3, ResultHandler var4) throws SQLException;

    <E> Cursor<E> queryCursor(MappedStatement var1, Object var2, RowBounds var3) throws SQLException;

    List<BatchResult> flushStatements() throws SQLException;

    void commit(boolean var1) throws SQLException;

    void rollback(boolean var1) throws SQLException;

    CacheKey createCacheKey(MappedStatement var1, Object var2, RowBounds var3, BoundSql var4);

    boolean isCached(MappedStatement var1, CacheKey var2);

    void clearLocalCache();

    void deferLoad(MappedStatement var1, MetaObject var2, String var3, CacheKey var4, Class<?> var5);

    Transaction getTransaction();

    void close(boolean var1);

    boolean isClosed();

    void setExecutorWrapper(Executor var1);
}

 private static final class ClosedExecutor extends BaseExecutor {
        public ClosedExecutor() {
            super((Configuration)null, (Transaction)null);
        }

        public boolean isClosed() {
            return true;
        }

        protected int doUpdate(MappedStatement ms, Object parameter) throws SQLException {
            throw new UnsupportedOperationException("Not supported.");
        }

        protected List<BatchResult> doFlushStatements(boolean isRollback) throws SQLException {
            throw new UnsupportedOperationException("Not supported.");
        }

        protected <E> List<E> doQuery(MappedStatement ms, Object parameter, RowBounds rowBounds, ResultHandler resultHandler, BoundSql boundSql) throws SQLException {
            throw new UnsupportedOperationException("Not supported.");
        }

        protected <E> Cursor<E> doQueryCursor(MappedStatement ms, Object parameter, RowBounds rowBounds, BoundSql boundSql) throws SQLException {
            throw new UnsupportedOperationException("Not supported.");
        }
    }

public class SimpleExecutor extends BaseExecutor {
    public int doUpdate(MappedStatement ms, Object parameter) throws SQLException {
        Statement stmt = null;

        int var6;
        try {
            //获得configuration
            Configuration configuration = ms.getConfiguration();
            //根据configuration获得对应的StatementHandler 后面讲
            StatementHandler handler = configuration.newStatementHandler(this, ms, parameter, RowBounds.DEFAULT, (ResultHandler) null, (BoundSql) null);
            stmt = this.prepareStatement(handler, ms.getStatementLog());
            var6 = handler.update(stmt);
        } finally {
            //释放Statement
            this.closeStatement(stmt);
        }

        return var6;
    }
    private Statement prepareStatement(StatementHandler handler, Log statementLog) throws SQLException {
        Connection connection = this.getConnection(statementLog);
        Statement stmt = handler.prepare(connection, this.transaction.getTimeout());
        handler.parameterize(stmt);
        return stmt;
    }
}